Initial import

1 files changed, 175 insertions, 0 deletions

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
new file mode 100644
index 000000000..883f6b933
--- /dev/null
+++ b/arch/x86/include/asm/mmu_context.h
@@ -0,0 +1,175 @@
+#ifndef _ASM_X86_MMU_CONTEXT_H
+#define _ASM_X86_MMU_CONTEXT_H
+
+#include <asm/desc.h>
+#include <linux/atomic.h>
+#include <linux/mm_types.h>
+
+#include <trace/events/tlb.h>
+
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/paravirt.h>
+#include <asm/mpx.h>
+#ifndef CONFIG_PARAVIRT
+static inline void paravirt_activate_mm(struct mm_struct *prev,
+					struct mm_struct *next)
+{
+}
+#endif	/* !CONFIG_PARAVIRT */
+
+#ifdef CONFIG_PERF_EVENTS
+extern struct static_key rdpmc_always_available;
+
+static inline void load_mm_cr4(struct mm_struct *mm)
+{
+	if (static_key_true(&rdpmc_always_available) ||
+	    atomic_read(&mm->context.perf_rdpmc_allowed))
+		cr4_set_bits(X86_CR4_PCE);
+	else
+		cr4_clear_bits(X86_CR4_PCE);
+}
+#else
+static inline void load_mm_cr4(struct mm_struct *mm) {}
+#endif
+
+/*
+ * Used for LDT copy/destruction.
+ */
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
+void destroy_context(struct mm_struct *mm);
+
+
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+#ifdef CONFIG_SMP
+	if (this_cpu_read(cpu_tlbstate.state) == TLBSTATE_OK)
+		this_cpu_write(cpu_tlbstate.state, TLBSTATE_LAZY);
+#endif
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	unsigned cpu = smp_processor_id();
+
+	if (likely(prev != next)) {
+#ifdef CONFIG_SMP
+		this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
+		this_cpu_write(cpu_tlbstate.active_mm, next);
+#endif
+		cpumask_set_cpu(cpu, mm_cpumask(next));
+
+		/* Re-load page tables */
+		load_cr3(next->pgd);
+		trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
+
+		/* Stop flush ipis for the previous mm */
+		cpumask_clear_cpu(cpu, mm_cpumask(prev));
+
+		/* Load per-mm CR4 state */
+		load_mm_cr4(next);
+
+		/*
+		 * Load the LDT, if the LDT is different.
+		 *
+		 * It's possible that prev->context.ldt doesn't match
+		 * the LDT register.  This can happen if leave_mm(prev)
+		 * was called and then modify_ldt changed
+		 * prev->context.ldt but suppressed an IPI to this CPU.
+		 * In this case, prev->context.ldt != NULL, because we
+		 * never free an LDT while the mm still exists.  That
+		 * means that next->context.ldt != prev->context.ldt,
+		 * because mms never share an LDT.
+		 */
+		if (unlikely(prev->context.ldt != next->context.ldt))
+			load_LDT_nolock(&next->context);
+	}
+#ifdef CONFIG_SMP
+	  else {
+		this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
+		BUG_ON(this_cpu_read(cpu_tlbstate.active_mm) != next);
+
+		if (!cpumask_test_cpu(cpu, mm_cpumask(next))) {
+			/*
+			 * On established mms, the mm_cpumask is only changed
+			 * from irq context, from ptep_clear_flush() while in
+			 * lazy tlb mode, and here. Irqs are blocked during
+			 * schedule, protecting us from simultaneous changes.
+			 */
+			cpumask_set_cpu(cpu, mm_cpumask(next));
+			/*
+			 * We were in lazy tlb mode and leave_mm disabled
+			 * tlb flush IPI delivery. We must reload CR3
+			 * to make sure to use no freed page tables.
+			 */
+			load_cr3(next->pgd);
+			trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
+			load_mm_cr4(next);
+			load_LDT_nolock(&next->context);
+		}
+	}
+#endif
+}
+
+#define activate_mm(prev, next)			\
+do {						\
+	paravirt_activate_mm((prev), (next));	\
+	switch_mm((prev), (next), NULL);	\
+} while (0);
+
+#ifdef CONFIG_X86_32
+#define deactivate_mm(tsk, mm)			\
+do {						\
+	lazy_load_gs(0);			\
+} while (0)
+#else
+#define deactivate_mm(tsk, mm)			\
+do {						\
+	load_gs_index(0);			\
+	loadsegment(fs, 0);			\
+} while (0)
+#endif
+
+static inline void arch_dup_mmap(struct mm_struct *oldmm,
+				 struct mm_struct *mm)
+{
+	paravirt_arch_dup_mmap(oldmm, mm);
+}
+
+static inline void arch_exit_mmap(struct mm_struct *mm)
+{
+	paravirt_arch_exit_mmap(mm);
+}
+
+static inline void arch_bprm_mm_init(struct mm_struct *mm,
+		struct vm_area_struct *vma)
+{
+	mpx_mm_init(mm);
+}
+
+static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
+			      unsigned long start, unsigned long end)
+{
+	/*
+	 * mpx_notify_unmap() goes and reads a rarely-hot
+	 * cacheline in the mm_struct.  That can be expensive
+	 * enough to be seen in profiles.
+	 *
+	 * The mpx_notify_unmap() call and its contents have been
+	 * observed to affect munmap() performance on hardware
+	 * where MPX is not present.
+	 *
+	 * The unlikely() optimizes for the fast case: no MPX
+	 * in the CPU, or no MPX use in the process.  Even if
+	 * we get this wrong (in the unlikely event that MPX
+	 * is widely enabled on some system) the overhead of
+	 * MPX itself (reading bounds tables) is expected to
+	 * overwhelm the overhead of getting this unlikely()
+	 * consistently wrong.
+	 */
+	if (unlikely(cpu_feature_enabled(X86_FEATURE_MPX)))
+		mpx_notify_unmap(mm, vma, start, end);
+}
+
+#endif /* _ASM_X86_MMU_CONTEXT_H */